Re: About VxWorks watchdog

My base line is:
If the task responsible for petting the HW watchdog running at the
highest priority could not pet the dog as expected, system stuck may
happen...

Just as Moto said, to spawn a task, so in your system, how to use in
this way? In which priority?
Furthermore, I agree using a timer is not a good way.

Michael R. Kesti wrote:
LarryC wrote:

Yes... Spawning a new task running a corresponding low priority (say 0)
to pet HW watchodg is good method.

Priority 0 would be a high priority task. Not sure either extreme is
what you want.

Right. In VxWorks, 0 is the highest task priority and HW watchdog maintenance
should probably not be a real time system's highest priority. If it is then
I would suspect that the dog's time constant is probably too short.

What is more, using a timer to schedule HW watchdog maintenance is probably
not an optimal approach. The idea is to generate a reset if the system's
mission is not being accomplished and, in most real time systems, the
ability to respond to a periodic timer is probably not highest on the
list of mission critical accomplishments. Instead, one would do well to
perform HW watchdog maintenance as the last step of a high priority task,
ideally after it has shown to have met its deadline.

--
========================================================================
Michael Kesti | "And like, one and one don't make
| two, one and one make one."
mrkesti at hotmail dot com | - The Who, Bargain

.

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